19-Nor deoxycorticosterone (19-nor-DOC) is a recently identified powerful nineralocorticoid. We have found that the urinary excretation of 19-nor-DOC is increased in rats with adrenal regeneration hpertension and others have found it markedly elevated in the pre-hypertensive stage of the spontaneously hypertensive rat (SHR). We propose to study the chronology of increased excretion rates of 19-nor-DOC in the urine and the precursor, 19-oic-DOC, in the plasma of rats during the development of ARH. The adrenal synthesis and regulation of 19-oic DOC will also be studied using in vivo and in vitro techniques. The peripheral conversion of 19-oic-DOC into 19-nor-DOC will also be studied by incubating various organs with (3H)-19-oic-DOC and measuring the formation of (3H)-19-nor-DOC. In addition, the role of 19-nor-DOC in the pathogenesis of two types of genetic hpertension, the SHR and Dahl's S & R strains of rats. Finally, we will search for the presence of other 19-oic-steroids in adrenal incubations. As standard methods of steroids almost guarantee the elimination of this type of steroid, it is not surprising that they have not been previously isolated.